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  #1  
Old 07-07-2008, 11:06 AM
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Bent my alternator bracket - should I be worried?

I have tried several different Mercedes "star" alternator bolts on my '78 300D and I just can't get them to work right - they will not tighten the belt enough. So, I have replaced the star bolt with a regular steel bolt, washers, and a nut from a hardware store (about the same size).

With a little leverage applied at the right place I was able to get the belt tight to FSM specs, but... I kept tightening the bolt/nut not realizing that I was bending the bracket in with the bolt. I stopped and everything seems tight and I drove the car for 750 miles w/o any loosening of the belt at all, but I have another 1400 miles to go to get home.

Should I be concerned that this 'fix' is going to give out on me?
And, can you still buy this bracket, or salvage item only?

ryan

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1984 300D
1972 250
1986 560SL
1991 300CE
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  #2  
Old 07-07-2008, 11:14 AM
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Bracket is for sale on this site. Do you have the cylindrical spacer for that top "star" bolt? I'm guessing you don't since that bracket is bent.
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1979 240D
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  #3  
Old 07-07-2008, 11:43 AM
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Cylindrical spacer???

Wow! $122 for that bracket!

I don't have time to order it online before we leave for home - I guess if it held for 750 miles already, it will get me home - I hope.

ryan
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1984 300D
1972 250
1986 560SL
1991 300CE
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  #4  
Old 07-07-2008, 06:02 PM
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As you said. If it's lasted this long then hopefully it will get you home. I would think that you can remove the alternator and bend that bracket back into position.
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  #5  
Old 07-07-2008, 06:10 PM
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How true is the belt riding in the pulley groove? If there is not a lot of skew, causing the belt to rub or pull down on the pulley shaft, you should make it home.
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  #6  
Old 07-07-2008, 06:31 PM
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It's been a while since I've replaced my belt, but from what I remember, the bracket, only serves to give you some tension, not to hold the belt in place - if it was hard to move in the first place, you may have missed loosening a bolt somewhere. (I want to say that I remember one being hidden, because I do remembering starting to bend mine, when I stopped and looked around some more).

Good Luck!
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  #7  
Old 07-09-2008, 10:50 AM
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Is there some kind of spacer that I am possibly missing - that prevents you from over-tightening and bending the bracket?

The belt looks like its riding pretty true to the pulley and it is still tight. Also, there are only 2 bolts on this alternator - a pivot bolt at the bottom and the 'star' bolt. I don't have trouble moving the alternator- just getting the belt to tighten right while adjusting the star bolt. I finally used a pry bar and a regular steel bolt and nut to get it tight.

ryan
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1984 300D
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  #8  
Old 07-09-2008, 10:57 AM
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nope, no spacer... stupid design really.
and there are 3 bolts holding the alternator... one holds the main bracket to the block, the other two go through the alternator into this bracket they all need to be loose to adjust properly, and they ALL need to be tight after you have the adjustment out of the belt.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
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  #9  
Old 07-09-2008, 11:16 AM
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But you only have to loosen 2 to adjust the alternator, right? The third just holds the bracket to the block - correct?

ryan
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1984 300D
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1986 560SL
1991 300CE
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  #10  
Old 07-09-2008, 12:16 PM
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sort of... the angle of the bracket needs to change as you loosen and tighten the alternator. so it's best to loosen all three.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #11  
Old 07-09-2008, 12:27 PM
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I had a similar problem on my 107. .I could work the star bolt to the top of the bracket and the belt wouldn't be tight enough, I replaced the bolt (as I had destroyed the star part and got a belt that was one inch smaller (I guess autozone's computer was wrong, not surprising) and that did the trick.

Be sure you bang all the bolts loose to remove any set in grime, the intracices of the tightening system foul up with oil and dirt.

Be sure to loosen the non adjusting bolt first then remove the back bolt off the star bolt and lightly tap it with the nut on, it should come off without damaging the self tightening system...I learned all this the hard way. . .
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  #12  
Old 07-09-2008, 01:05 PM
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Quote:
Originally Posted by vstech View Post
nope, no spacer... stupid design really.
and there are 3 bolts holding the alternator... one holds the main bracket to the block, the other two go through the alternator into this bracket they all need to be loose to adjust properly, and they ALL need to be tight after you have the adjustment out of the belt.
Mine has a metal cylinder about an 4cm in length. Maybe this is some kind of mod because the replacement alternator was not OEM. I'll try to take a picture. Clearly it functions to keep from bending the bracket as you tighten the adjusting bolt.
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  #13  
Old 07-09-2008, 06:19 PM
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Are you sure that section of the bracket the adjustment rod goes through is "boxed" so to speak. I think when some people replace these alternators they bend away that section of the bracket to make it easier to install the adjusting bolt and then never bend it back under. There's no way that bracket is going to bend if that box section is in place. That's what it's there for, to prevent bending. Check page 69 of a Performance Parts catalogue. The brackets facing backwards but you should be able to see what I mean.
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  #14  
Old 07-09-2008, 09:12 PM
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rgnprof, this is the spacer I was trying to describe. I hope this helps.
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1979 240D
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  #15  
Old 07-09-2008, 09:31 PM
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Do'h... sorry, I missed the 78 part...
I can take a look at my 78 and get back to you...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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